Hot-fill container base structure

ABSTRACT

The invention provides a base structure of a container. The base structure includes a support heel that defines any number of touch points for contact with a horizontal surface. The support heel includes inner and outer portions that merge with the container&#39;s corrugated support flute and sidewall, respectively. The base structure also includes a fin that forms the zipper pinch and extends transverse to and intersects corrugations of the corrugated support flute.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates generally to a container having abase structure for enhancing the structural integrity of the container.

[0003] 2. Related Art

[0004] The warehouse club industry and consumer bulk purchasing have ledto a boom in larger size packaging. Many liquid products are now sold tothe consuming public in plastic containers that can be as large as 128fluid ounces (one gallon). Larger containers that hold heavy fluids,including beverages, home products, motor oil, or the like, require abase structure that can withstand the forces applied against it, such asthe weight of the fluid itself. Additionally, the containers mustwithstand rough handling during transportation and other forces appliedto them as a result of being stacked during storage or from beingdropped. Finally, large beverage containers that are filled by theso-called hot-fill process must be structurally sound to withstandvarious forces relating to the hot-fill process.

[0005] The hot-fill process is the procedure by which containers arefilled with a beverage at a high temperature and capped soon thereafter.As the beverage cools within the container, stresses and strains developin the container due to changes in the volume of the contents. In thecase of large containers, the hot-fill process can cause, among otherthings, sagging in the base and rolls in the corners of the container.

[0006] A container that is commonly used in the hot-fill process is thepolyolefin continuous extrusion blow-molded container. Polyolefincontinuous extrusion blow-molded container's are multi-layer containersthat provide the requisite structure and barriers to oxygen and oils,for example. These multi-layered containers typically include anexterior layer of polyolefin, such as, polypropylene or polyethylene asthe main structure providing layer. Other layers can include oxygenbarrier layers, moisture barrier layers, and regrind layers to providethe necessary barrier structures, as well as, adhesion between thelayers.

[0007] It is understood by a person having ordinary skill in the artthat to form a polypolefin continuous extrusion blow-molded plasticcontainer, a parison can be heated in an extruder, captured by a mold,and blown in the mold. Specifically, to form the cavity of thecontainer, a parison can be extruded up into the mold and as the moldcomes together, a pneumatic blow pin, for example, can pierce theparison and blow the parison up against the walls of the mold. The moldtypically contains flash pockets above and below the cavity in the moldto capture the excess parison above and below the cavity. It can beunderstood by a person having ordinary skill in the art, that as theparison is blown inside the mold and captured in the flash pockets,portions of the parison must adhere together. Once the container iscooled, the excess flash can then be cut away from the container afterbeing ejected from the mold.

[0008] The desire to provide structural integrity to large containershas resulted in the development of different techniques to designcontainers that have structurally sound bases. The introduction ofdifferent structural elements into the base of the container is known toimprove the containers structural integrity. While these structuralelements molded in the base's structure can afford structural integrity,they must also be able to withstand the forces of the hot-fill process.

[0009] Although the aforementioned structural elements may functionsatisfactorily for their intended purposes, there is a need for a largecontainer having a base structure that can withstand the forces of thehot-fill process. The base structures should be capable of accommodatingvariations in volume of the containers' contents and changes of pressureand temperature. Furthermore, the base structure should be capable ofbeing manufactured in conventional high-speed equipment.

SUMMARY OF THE INVENTION

[0010] A base structure for a hot-fill container is disclosed.

[0011] Particular embodiments of the invention provide a base structureof a container. In one embodiment, the base structure includes a supportheel that defines any number of touch points for contact with ahorizontal surface. The support heel includes inner and outer portionsthat merge with the container's corrugated support flute and sidewall,respectively. The base structure also includes a fin that extendstransverse to and intersects corrugations of the corrugated supportflute.

[0012] In a further embodiment, the base structure includes a supportheel that defines any number of touch points for contact with ahorizontal surface. The support heel includes inner and outer portionsthat merge with the container's plurality of ribs and sidewall,respectively. Each rib has two ends that merge with the support heel.The base structure also includes a fin that extends transverse to andintersects at least one rib.

[0013] Yet another embodiment of the invention provides a container thathas a neck portion, base structure, and sidewall. The neck portiondefines an opening and the sidewall merges with the base structure andthe neck portion at opposite ends of the container. The base structureincludes a support heel that defines any number of touch points forcontact with a horizontal surface. The support heel includes inner andouter portions that merge with the container's corrugated support fluteand sidewall, respectively. The base structure also includes a fin thatextends transverse to and intersects corrugations of the corrugatedsupport flute.

[0014] Further features and advantages of the invention, as well as thestructure and operation of various embodiments of the invention, aredescribed in detail below with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The foregoing and other features and advantages of the inventionwill be apparent from the following, more particular description ofpreferred embodiments of the invention, as illustrated in theaccompanying drawings wherein like reference numbers generally indicateidentical, functionally similar, and/or structurally similar elements.

[0016]FIG. 1 depicts a perspective view of an exemplary embodiment of ahot-fill container according to the present invention;

[0017]FIG. 2 depicts a base structure of an exemplary embodiment of ahot-fill container according to the present invention;

[0018]FIG. 3 depicts a perspective view of a base structure of anexemplary embodiment of a hot-fill structure according to the presentinvention;

[0019]FIG. 4 depicts a perspective view of a base structure of anexemplary embodiment of a hot-fill structure according to the presentinvention;

[0020]FIG. 5 depicts a cross-sectional view along section line 5-5 inFIG. 2; and

[0021]FIG. 6 depicts a cross-sectional view along section line 6-6 inFIG. 2.

DETAILED DESCRIPTION OF THE INVENTION

[0022] Preferred embodiments of the invention are discussed in detailbelow. While specific exemplary embodiments are discussed, it should beunderstood that this is done for illustration purposes only. A personskilled in the relevant art will recognize that other components andconfigurations can be used without parting from the spirit and scope ofthe invention.

[0023] There are several currently existing structures that can providesupport for the base of a hot-fillable container. For example, acorrugated support flute, most commonly used in laundry detergentcontainers that are not hot-filled, includes any number of corrugationsto provide resistance against sagging caused by the weight of the liquiditself. The corrugated support flutes also provides structure to assistthe base in maintaining its designed shape and resisting warpage whilethe plastic is cooling prior to the filling process.

[0024] Similarly, a fin can be constructed into the pinch area of thebase to give additional stability to the area in the base where piecesof parison fuse together. For example, in beverage bottles or the likethat contain a gas barrier, a fin can provide a larger area near thebase of the bottle for the pieces of parison to amalgamate and adhere toeach other. Like the corrugated support flute, the fin also providesstructure to assist the base in maintaining its designed shape andresisting warpage while the plastic is cooling prior to the fillingprocess.

[0025] In the context of large, hot-fillable containers, thesestructures, when used independently, tend to be less effective. Forexample, a one gallon container having corrugations alone is lessdesirable because it would require a push-up so deep that the undercutsin the mold may not be pulled through when the container is releasedfrom the mold. Additionally, given the weight of the liquid to be placedin the container, a corrugated support flute alone may not provide foradequate adhesion and cause the plastic in the base to pull apart.

[0026] Like the corrugated support flute, a fin alone is less desirablebecause although it may provide for adequate adhesion, it will notlikely provide enough support to prevent sagging. Thus, it is desirableto provide a base structure for a large container, preferably for use inthe hot-fillable process, with adequate structure to prevent sagging andprovide for adhesion of the parison in the base of the container.

[0027] Referring now to the drawings, FIG. 1 illustrates an exemplaryembodiment of a blow-molded plastic container 10, such as may be used inthe sale of juices and non-carbonated beverages. Such containers cantypically be designed to contain liquid volumes of one gallon, 64ounces, or the like. Container 10 can have a neck portion 11 defining anopening 12 allowing for pouring and filling of a beverage. Neck portion11 merges with sidewall 13. Depending upon the cross-sectional shape ofcontainer 10, sidewall 13 can have any number of sides. For example, asshown in FIG. 1, container 10 has 4 sides defined by the container'srectangular cross-sectional shape. Sidewall 13 can also include upperlabel bumper 17 and lower label bumper 18. These label bumpers can bepositioned on container 10 near where sidewall 13 merges with neckportion 11 and base structure 14, respectively. Sidewall 13 merges withbase structure 14 opposite neck portion 11.

[0028] Container 10 is designed to receive a cap (not shown) during thehot-fill process to seal the container and confine the beverage insidethe container. While sidewall 13 is shown as a rectangularcross-sectional sidewall, any shape can be utilized, such as a square ortriangular cross-sectional sidewall, or a cylinder. It is understood bypeople having ordinary skill in the art that the edges of the containercan be rounded and although the container may be rectangular, the edgesmay not form perfect right angles. In such an embodiment, base structure14 would be shaped appropriately to merge with sidewall 13.

[0029] Container 10 can also include a handle 16 for receiving the gripof a consumer's hand. As shown in FIG. 5, handle 16 can be hollow andthus able to store fluid when container 10 is filled.

[0030] Base structure 14 can be arcuate or dome-like such that the baseof the container can define touch points at which the base of thecontainer makes contact with a horizontal surface (not shown). Forexample, base structure 14 of container 10 can be arched towards thecenter of the container so as to define four touch points 15 a-d asshown in FIGS. 1-4. As sagging occurs, whether it be from the weight ofthe liquid itself or as a result of the hot-fill process, the archingcan ensure that no portion of base structure 14 sags below touch points15 a-d. This arching up into the center of container 10 can be calledrocker correction.

[0031] In addition to rocker correction, base structure 14 also caninclude structure that can, among other things, prevent sagging. As seenin FIG. 2, base structure 14 has an annular support heel 21. Supportheel 21 allows container 10 to be supported erect on a horizontalsurface. Like sidewall 13, support heel 21 can have any number of sides,depending on the cross-sectional shape of the container. For example,support heel 21 can have 4 sides that are defined by the container'srectangle cross-sectional shape. Two of these sides can extendsubstantially parallel to each other in a longitudinal direction, whilethe other two sides can extend substantially parallel to each other in adirection that is transverse to the longitudinal direction. As describedabove, each side of support heel 21 can be arched toward the center ofcontainer 10 to define touch points 15 a-d. The apex of the arc thatextends in the longitudinal direction can be, for example, 0.080 inchesfrom touch points 15 a-d. Similarly, the apex of the arc extending inthe transverse direction can be, for example, 0.120 inches from touchpoints 15 a-d.

[0032] Annular support heel 21 can have an inner and an outer portion,22 and 23, respectively. Outer portion 23 merges with the container'ssidewall 13. The inner portion of the annular support heel, which mergeswith a corrugated support flute 24, can have an upwardly inclinedsurface that angles upward from support heel 21 to corrugated supportflute 24, as shown in FIGS. 3 and 4. The upwardly inclined surface ofinner portion 22 can be as inclined as possible so long as the undercutsin the mold can be pulled through once the container is blown.Otherwise, if the upwardly inclined surface of inner portion 22 is attoo great of an inclination, the undercuts in the mold may cock thecontainer in a sideways direction and not allow the container to bereleased from the mold properly.

[0033] Corrugated support flute 24 can have any number of corrugations(ribs) 29 extending across any portion of corrugated support flute 24.For example, as shown in FIG. 2, corrugated support flute 24 can have 5corrugations 29. As shown in FIG. 5, each corrugation 29 can have awidth “w” that extends between the centers of adjacent corrugations 29and a depth “d” that extends from the top of the inside of basestructure 14 down into each corrugation 29. In a preferred embodiment,corrugated support flute 24 can also have flat surfaces 51 a-b that canconnect the outer-most corrugations 29 to inner portion 22 of annularsupport heel 21. Surfaces 51 a-b can receive engraved symbols such as,for example, the SPI recycling code, the manufacturer's logo, the cavitynumber, or the set designation.

[0034] Positioned transverse to the corrugated support flute 24 is a fin25. It can be understood by a person having ordinary skill in the artthat fin 25 will be located in the pinch area of base structure 14 ofcontainer 10. Fin 25 can extend in a longitudinal direction, forexample, and intersect any portion of any of corrugations 29 ofcorrugated support flute 24. In a preferred embodiment, fin 25 canintersect all corrugations 29 of corrugated support flute 24 through thecenter of each corrugation 29, as shown in FIGS. 2-5.

[0035] Fin 25 can have a beam 26 extending transverse to corrugatedsupport flute 24 and a plurality of protrusions 27 that arealternatively positioned on either side of beam 26 to form a so-calledzippered pinch. Beam 26 can extend in a longitudinal direction, forexample, and merge with inner portion 22 of annular support heel 21. Ina preferred embodiment, the alternatively positioned protrusions 27 mayoverlap. As shown in FIGS. 5 and 6, beam 26 may extend below protrusions27. Additionally, in a preferred embodiment, the top side of fin 25 canfollow the contour of corrugations 29 of corrugated support flute 24. Ina similar fashion, protrusions 27 may also follow the contour ofcorrugations 29 of corrugated support flute 24.

[0036] In a preferred embodiment of the invention, base structure 14 canhave tunnels 28. As described above, the mold typically contains flashpockets above and below the cavity in the mold to capture the excess ofthe parison that is captured in the flash pockets above and below thecavity. Tunnels 28 can provide a channel for the excess parison totravel through as the excess parison is forced into the flash pockets.

[0037] It is the combination of corrugated support flute 24 and thepositioning of fin 25 transverse to the corrugated support flute thatallows the base structure of the present invention to provide thedesired structural integrity of the container bottom. The support fluteand the zipper pinch will act in a manner to withstand the changes intemperature, pressure, and volume within the container during thehot-fill process, as well as other forces applied to it during theconstruction, transportation, and storage of the container. The supportflute and the zipper pinch cooperate to resist sagging of the base byproviding the necessary structure to withstand all forces applied to thecontainer. Additionally, the vertical beam and zipper pinch of the finresists deformation of the base structure.

[0038] While various embodiments of the present invention have beendescribed above, it should be understood that they have been presentedby way of example only, and not limitation. Thus, the breadth and scopeof the present invention should not be limited by any of theabove-described exemplary embodiments, but should instead be definedonly in accordance with the following claims and their equivalents.

What is claimed is:
 1. A base structure for a container having a sidewall, the base structure comprising: a support heel defining a touch point for contact with a horizontal surface, the support heel having an outer portion and an inner portion, the outer portion merging with the container sidewall; a corrugated support flute having corrugations surrounded by the support heel and merging with the inner portion of the support heel; and a fin extending transverse to and intersecting at least one of the corrugations of the corrugated support flute.
 2. The base structure according to claim 1, wherein the fin further comprises: a beam having first and second sides, the second side being opposite and substantially parallel to the first side; and a plurality of protrusions alternatively positioned on the first and second sides of the beam.
 3. The base structure according to claim 2, wherein at least one pair of adjacent alternatively position protrusions overlap.
 4. The base structure according to claim 1, wherein the fin further comprises: a zigzag curve extending in a longitudinal direction; and a beam extending in the longitudinal direction and intersecting the zigzag curve.
 5. The base according to claim 1, wherein the corrugations extend in a first direction and a center of each corrugation defines a midpoint of the base structure in the first direction, and the fin extends in a second direction substantially perpendicular to the first direction and substantially through the center of each corrugation.
 6. The base structure according to claim 1, wherein the inner portion of the support heel is an upwardly inclined surface.
 7. The base structure according to claim 1, wherein the support heel provides a circumferential line of support.
 8. The base structure according to claim 1, wherein the support heel provides an annular line of support.
 9. The base structure according to claim 1, further comprising: a flat surface that merges with the corrugations and the inner portion of the support heel.
 10. The base structure according to claim 1, wherein the support heel defines four touch points.
 11. The base structure according to claim 10, wherein the fin further comprises: a beam having first and second sides, the second side being opposite and substantially parallel to the first side; and a plurality of protrusions alternatively positioned on the first and second sides of the beam.
 12. The base structure according to claim 11, wherein at least one pair of adjacent alternatively positioned protrusions overlap.
 13. A base structure according to claim 10, wherein the fin further comprises: a zigzag curve extending in a longitudinal direction; and a beam extending in the longitudinal direction and intersecting the zigzag curve.
 14. The base structure according to claim 10, wherein the corrugations extend in a latitudinal direction and a center of each corrugation defines a midpoint of the base structure in the latitudinal direction, and the fin extends in a longitudinal direction substantially perpendicular to the latitudinal direction and substantially through the center of each corrugation.
 15. The base structure according to claim 10, wherein the inner portion of the support heel is an upwardly inclined surface.
 16. A base structure according to claim 10, wherein the support heel is substantially rectangular.
 17. The base structure according to claim 10, further comprising: a flat surface that merges with the corrugations and the inner portion of the support heel.
 18. A base structure for a container having a sidewall, the base structure comprising: a support heel defining a touch point for contact with a horizontal surface, the support heel merging with the container sidewall; a plurality of ribs, each rib having two ends that merge with the support heel; and a fin extending transverse to and intersecting at least one of the ribs.
 19. The base structure according to claim 18, wherein the fin further comprises: a beam having first and second sides, the second side being opposite and substantially parallel to the first side; and a plurality of protrusions alternatively positioned on the first and second sides of the beam.
 20. The base structure according to claim 19, wherein at least one pair of adjacent alternatively positioned protrusions overlap.
 21. The base structure according to claim 18, wherein the fin comprises: a zigzag curve extending in a longitudinal direction; and a beam extending in the longitudinal direction and intersecting the zigzag curve.
 22. The base structure according to claim 18, wherein the ribs extend in a first direction and a center of each rib defines a midpoint of the base structure in the first direction, and the fin extends in a second direction substantially perpendicular to the first direction and substantially through the center of each rib.
 23. The base structure according to claim 18, wherein the support heel defines four touch points.
 24. The base structure according to claim 16, further comprising: a flat surface that merges with the corrugations and the inner portion of the support heel.
 25. A container comprising: a neck portion defining an opening; a base structure; and a sidewall that merges with the base structure and the neck portion at opposite ends of the container, wherein the base structure has: a support heel defining a touch point for contact with a horizontal surface, the support heel having an outer portion and an inner portion, the outer portion merging with the container sidewall; a corrugated support flute having corrugations surrounded by the support heel and merging with the inner portion of the support heel; and a fin extending transverse to and intersecting at least one of the corrugations of the support flute. 